Are the center pilot bearing on the CV driveshaft the same? What years did they change?

79-85 and 86-up are different, I think  I can check tomorrow if you like; I don't have a ujoint book here at home.(maybe I should.. )  IIRC, 79-85 is a .413" and the later is a .5?? CBAssy.  I went through this about 8-10 months ago.  I had a hell of a time with the ball, so I called Marlin.  I was referred to Jesse @ high angle driveline.  I told him what was up, he said the best thing I could do was NOT replace the ball.  I also had a Precision kit.  I was told that their ball kits are junk. 

I am not saying their ujoints are bad, that is what I run, and I have no firsthand experience with a CB failure, this is just what Jesse told me.